scholarly journals Three-dimensional in-situ imaging of cracks in concrete using diffuse ultrasound

2017 ◽  
Vol 17 (2) ◽  
pp. 279-284 ◽  
Author(s):  
Yuxiang Zhang ◽  
Eric Larose ◽  
Ludovic Moreau ◽  
Grégoire d’Ozouville
Keyword(s):  
Wind Tunnel ◽  
Multiple Scattering ◽  
Structural Changes ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Thick Wall ◽  
Pressure Changes ◽  
Diffuse Ultrasound

Locadiff, an innovative imaging technique based on diffuse waves, has recently been developed in order to image mechanical changes in heterogeneous, geological, or man-made materials. This manuscript reports the on-site application of Locadiff to locate several pre-existing cracks on an aeronautical wind tunnel made of pre-stressed concrete. Using 32 transducers working at ultrasonic frequencies (80–220 kHz) where multiple scattering occurs, we monitor during 15 min an area of 2.5 m×2.5 m of a 35-cm-thick wall. With the wind tunnel in its routine operation, structural changes around the cracks are detected, thanks to their closing or opening due to slight pressure changes. By mapping the density of such microstructure changes in the bulk of the material, locating three pre-existing cracks is properly performed in three dimensions.

Three Dimensional Replication of Fatigue Cracks by Vacuum Infiltration for Study of Crack Tip Morphology by Scanning Electron Microscopy

1970 ◽  
Vol 28 ◽  
pp. 402-403
Author(s):  
G. G. Shaw
Keyword(s):  
Fatigue Cracks ◽  
Three Dimensional ◽  
Crack Tip ◽  
Vacuum Infiltration ◽  
Three Dimensions ◽  
New Information ◽  
Crack Tips ◽  
Sheet Sample ◽  
Scanning Electron

I. Introduction: Fatigue investigators have been looking at crack tips by examining the surface and by sectioning the crack. Much useful information has been obtained by these methods, but a look at the complete crack in three dimensions with the tip intact yields much new information. This is especially true when one is able to examine the crack tip in full tension or compression or stages in between, by using the following techniques.II. Vacuum Infiltration in Situ: The crack is generated on a fatigue machine using a sheet sample with a notched central hole. If one desires to replicate in full tension, the machine is stopped in tension and the apparatus shown in Figure 1 is clamped to the sides of the sample.

A Unified Correction Method for the Acoustic Refraction (UCMAR) Caused by a Three Dimensional Shear Layer

2019 ◽  
Vol 105 (5) ◽  
pp. 732-742
Author(s):  
Lican Wang ◽  
Rongqian Chen ◽  
Yancheng You ◽  
Wenjun Wu ◽  
Ruofan Qiu
Keyword(s):  
Wind Tunnel ◽  
Temperature Gradient ◽  
Shear Layer ◽  
Ray Tracing ◽  
Three Dimensional ◽  
Correction Method ◽  
Three Dimensions ◽  
Acceptable Solution ◽  
One Dimensional ◽  
Planar Shear

The acoustic refraction induced by the shear layer in an open-jet wind tunnel causes a source shift when estimating the source location with beamforming. Traditional correction methods of the shear layer refraction are achieved through a computational eff ort or limited using one-dimensional or planar shear layer. In this paper, the unified correction method for acoustic refraction (UCMAR) is suitable for the three dimensions that covers several traditional forms. Meanwhile, the UCMAR can consider more general configurations, such as the temperature gradient on both sides of the shear layer and the off -axis source in a circular wind tunnel. These configurations are validated through a ray tracing technique and a benchmark example. In addition, the principle of time reverse is integrated with UCMAR. This results in a reverse UCMAR, which can quickly attain an acceptable solution.

scholarly journals Development of synchrotron X-ray micro-tomography under extreme conditions of pressure and temperature

2017 ◽  
Vol 24 (1) ◽  
pp. 240-247 ◽  
Author(s):  
M. Álvarez-Murga ◽  
J. P. Perrillat ◽  
Y. Le Godec ◽  
F. Bergame ◽  
J. Philippe ◽  
...  
Keyword(s):  
High Pressure ◽  
Structural Changes ◽  
Three Dimensional ◽  
Crystallographic Structure ◽  
Three Dimensional Imaging ◽  
X Ray ◽  
Wide Range ◽  
Micro Tomography ◽  
Non Destructive

X-ray tomography is a non-destructive three-dimensional imaging/microanalysis technique selective to a wide range of properties such as density, chemical composition, chemical states and crystallographic structure with extremely high sensitivity and spatial resolution. Here the development of in situ high-pressure high-temperature micro-tomography using a rotating module for the Paris–Edinburgh cell combined with synchrotron radiation is described. By rotating the sample chamber by 360°, the limited angular aperture of ordinary high-pressure cells is surmounted. Such a non-destructive high-resolution probe provides three-dimensional insight on the morphological and structural evolution of crystalline as well as amorphous phases during high pressure and temperature treatment. To demonstrate the potentials of this new experimental technique the compression behavior of a basalt glass is investigated by X-ray absorption tomography, and diffraction/scattering tomography imaging of the structural changes during the polymerization of C60 molecules under pressure is performed. Small size and weight of the loading frame and rotating module means that this apparatus is portable, and can be readily installed on most synchrotron facilities to take advantage of the diversity of three-dimensional imaging techniques available at beamlines. This experimental breakthrough should open new ways for in situ imaging of materials under extreme pressure–temperature–stress conditions, impacting diverse areas in physics, chemistry, geology or materials sciences.

scholarly journals Utilizing broadband X-rays in a Bragg coherent X-ray diffraction imaging experiment

2016 ◽  
Vol 23 (5) ◽  
pp. 1241-1244 ◽  
Author(s):  
Wonsuk Cha ◽  
Wenjun Liu ◽  
Ross Harder ◽  
Ruqing Xu ◽  
Paul H. Fuoss ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Three Dimensions ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Individual Crystal ◽  
Sample Motion ◽  
Diffraction Imaging ◽  
Individual Grains

A method is presented to simplify Bragg coherent X-ray diffraction imaging studies of complex heterogeneous crystalline materials with a two-stage screening/imaging process that utilizes polychromatic and monochromatic coherent X-rays and is compatible within situsample environments. Coherent white-beam diffraction is used to identify an individual crystal particle or grain that displays desired properties within a larger population. A three-dimensional reciprocal-space map suitable for diffraction imaging is then measured for the Bragg peak of interest using a monochromatic beam energy scan that requires no sample motion, thus simplifyingin situchamber design. This approach was demonstrated with Au nanoparticles and will enable, for example, individual grains in a polycrystalline material of specific orientation to be selected, then imaged in three dimensions while under load.

Measurement of three-dimensional lung tree structures by using computed tomography

1995 ◽  
Vol 79 (5) ◽  
pp. 1687-1697 ◽  
Author(s):  
S. A. Wood ◽  
E. A. Zerhouni ◽  
J. D. Hoford ◽  
E. A. Hoffman ◽  
W. Mitzner
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Central Axis ◽  
Segment Length ◽  
Cross Sectional ◽  
Tree Structures ◽  
Branch Segment ◽  
Tomography Data

A method was devised to computationally segment and measure three-dimensional pulmonary trees in situ. Bronchi and pulmonary vessels were computationally extracted from volumetric computed tomography data based on radiopacity differences between airway wall and airway lumen and between blood and parenchyma, respectively. The tree was reduced to a central axis to facilitate measurement of branch segment length and angle. Cross-sectional area was measured on a reconstructed computed tomography slice perpendicular to this central axis. The method was validated by scanning two Plexiglas phantoms and an intact lung. Reconstructed diameters in the phantoms were accurate for branches > 2 mm. In the lung airway branches between 1 and 2 mm in diameter were often unresolved when their angle of orientation with respect to the axis of the scanner was > 45 degrees. However, if a branch was resolved, its reconstructed diameter was little affected by orientation. This method represents a significant improvement in the analysis of complex pulmonary structures in three dimensions.

scholarly journals Tipping solutions: emerging 3D nano-fabrication/ -imaging technologies

Nanophotonics ◽  
2017 ◽  
Vol 6 (5) ◽  
pp. 923-941 ◽  
Author(s):  
Gediminas Seniutinas ◽  
Armandas Balčytis ◽  
Ignas Reklaitis ◽  
Feng Chen ◽  
Jeffrey Davis ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Imaging Technique ◽  
Ion Beam ◽  
Three Dimensional ◽  
Molecular Systems ◽  
Force Microscopy ◽  
Nano Fabrication ◽  
Atomic Force ◽  
Scanning Electron

AbstractThe evolution of optical microscopy from an imaging technique into a tool for materials modification and fabrication is now being repeated with other characterization techniques, including scanning electron microscopy (SEM), focused ion beam (FIB) milling/imaging, and atomic force microscopy (AFM). Fabrication and in situ imaging of materials undergoing a three-dimensional (3D) nano-structuring within a 1−100 nm resolution window is required for future manufacturing of devices. This level of precision is critically in enabling the cross-over between different device platforms (e.g. from electronics to micro-/nano-fluidics and/or photonics) within future devices that will be interfacing with biological and molecular systems in a 3D fashion. Prospective trends in electron, ion, and nano-tip based fabrication techniques are presented.

Three-dimensional electron delocalization: a theoretical study based on the pentacyclo[3.3.1.13,7.01,3.05,7]decane system

1997 ◽  
Vol 75 (2) ◽  
pp. 192-201 ◽  
Author(s):  
Mary S.W. Chan ◽  
Donald R. Arnold
Keyword(s):  
Radical Cation ◽  
Radical Anion ◽  
Structural Changes ◽  
Three Dimensional ◽  
Radical Cations ◽  
Three Dimensions ◽  
Electron Delocalization ◽  
Dimensional Electron ◽  
Frontier Orbitals ◽  
Dft Methods

The concept of electron delocalization, and the possibility of aromaticity in three dimensions has been introduced, but remains relatively unexplored. This work examines the structure and energy of a series of ions generated from pentacyclo[3.3.1.13,7.01,3.05,7]decane (1). The ions considered are the dication (12+), the radical cation (1+•), the radical anion (1−•), and the dianion (12−). The dication belongs to a small group of organic compounds that shows three-dimensional electron delocalization and it has been classified as "three-dimensionally homoaromatic." The relative stability of these ions is estimated by the enthalpy change of isodesmic and disproportionation reactions using energies obtained from HF, MP2, and DFT methods. The structural changes and the reorganization of the frontier orbitals when electrons are successively added to or removed from the neutral molecule (1) are also explored. The results confirm the three-dimensional electron delocalization in 12+ and indicate that it is stable relative to a localized structure with similar features; however, it is highly unstable compared to the radical cation (1+•). The dianion (12−), on the other hand, did not show any evidence for electron delocalization and it is unstable relative to the radical anion (1−•). Keywords: three-dimensional aromaticity, electron derealization, resonance, radical cations, radical anions.

Three-dimensional confocal morphometry reveals structural changes in astrocyte morphology in situ

2007 ◽  
Vol 85 (2) ◽  
pp. 260-271 ◽  
Author(s):  
Alexandr Chvátal ◽  
Miroslava Ande˘rová ◽  
Miroslav Hock ◽  
Iva Prajerová ◽  
Helena Nepras˘ová ◽  
...  
Keyword(s):  
Structural Changes ◽  
Three Dimensional

In situ microtomy and serial block face imaging by SEM

1992 ◽  
Vol 50 (1) ◽  
pp. 778-779 ◽  
Author(s):  
Alan M. Kuzirian ◽  
Stephen B. Leighton
Keyword(s):  
Three Dimensional ◽  
Three Dimensions ◽  
Dimensional Structure ◽  
Form And Function ◽  
Central Focus ◽  
Block Face ◽  
And Function ◽  
Flow Of Information ◽  
The Brain

The ability to view objects, including subcellular structures, in three-dimensions is crucial to understanding their form and function. For example, the three-dimensional (3-D) structure of the brain and its neurons has been the central focus of neuroanatomists for well over 100 years. Yet, what role a nerve cell’s three dimensional structure plays in controlling the flow of information within the nervous system remains a mystery. Part of the problem has been the difficulty in obtaining an accurate 3-D picture of a nerve cell’s shape as well as documenting its synaptic interconnections. Although many neurobiologists have turned to biochemical studies in recent years, it is becoming clear that precise structure and network diagrams will be necessary to relate the work of cell biologists with that of computational neuroscientists.

scholarly journals Multiphoton Microscopy: A Potential Intraoperative Tool for the Detection of Carcinoma In Situ in Human Bladder

2015 ◽  
Vol 139 (6) ◽  
pp. 796-804 ◽  
Author(s):  
Manu Jain ◽  
Brian D. Robinson ◽  
Maria M. Shevchuk ◽  
Amit Aggarwal ◽  
Bekheit Salamoon ◽  
...  
Keyword(s):  
Carcinoma In Situ ◽  
Interobserver Agreement ◽  
Imaging Technique ◽  
Multiphoton Microscopy ◽  
Three Dimensional ◽  
Predictive Values ◽  
Diagnostic Potential ◽  
Subcellular Resolution ◽  
Hematoxylin Eosin

Context Urothelial carcinoma in situ (CIS) is a precursor of invasive bladder cancer, which if left untreated, will likely progress to more aggressive disease. Approximately 50% of CIS lesions are missed on routine cystoscopy owing to their flat architecture. Furthermore, many benign but abnormal-appearing areas may be biopsied owing to lack of cellular resolution of cystoscopes. Multiphoton microscopy (MPM) is an optical imaging technique that generates subcellular-resolution three-dimensional images from unfixed tissue without using exogenous dyes. Objective To assess the diagnostic potential of MPM in identifying and differentiating benign from malignant flat bladder lesions, especially CIS. Design Seventy-eight specimens (benign = 46, CIS = 23, invasive = 9, as diagnosed on histopathology) were obtained from flat bladder mucosa via transurethral resection of bladder, cold cup biopsy, or cystectomy, imaged fresh with a commercial benchtop MPM, and submitted for routine histopathology. Multiphoton microscopy and hematoxylin-eosin diagnoses were compared. Results In 77 of 78 specimens (99%), accurate MPM diagnoses (benign/malignant) were given on the basis of their architectural and cytologic features (nuclear to cytoplasmic ratio, pleomorphism, polarity/organization of urothelial layers, etc). The sensitivity and specificity were 97% and 100%, respectively, with positive (malignant) and negative (benign) predictive values of 100% and 98%, respectively. The interobserver agreement, κ, was 0.93. Conclusions Our study demonstrates the capability of MPM to identify and differentiate benign from malignant flat bladder lesions, especially CIS. With the advent of MPM endoscopes, we foresee their potential as a biopsy guidance tool for early detection and treatment of CIS, thus reducing the rate of biopsies with benign diagnoses and their associated complications.

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